Pulsating screen for pulp and the like.



T. QVILLER. PULSA'IING SCREEN FOR PULP AND THE LIKE.

APPLICATION FI LBD NOV. 11, 1913.

Patented Jan. 12, 1915.

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T. QVILLER. PULSATING SCREEN FOR PULP AND THE LIKE.

APPLICATION FILED NOV. 11, 1913.

Patented Jan. 12, 1915.

2 SHEETS-SHEET 2.

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. PULSATING SCREEN FOR PULP AND THE LIKE.

Specification of Letters Patent. Patented J an, 12, 1915,

Application filed lqovember 11,1913. Serial No. 800,333.

To all whom may concern Be it known that I, THEODOR Qvn nnn, a subject of the King of Norway, resldmg at Lillestrtimmen near Christianra, "Nor way, have invented certain. new and useful Improvements in Pulsating Screens for Pulp and the like; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in'the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to the letters or figures of reference marked thereon, which form a part of this sp fi a ieni My" invention relates to pulsating screens for pulp and the like and has for 1ts ob ect to provide a'newscreening apparatus of the kind :ef erred to, the main feature of the said new appalffl l s consisting lIlAtS-httVlIlg no reciprocating parts to cause undesirous vibrations and shocks during the operation of the screen.

My invent-ion consists in the features of construction and combination of parts hereinafter described and illustrated on the accompanying drawings and more particularly as polnted out in the clalms.

On the drawings: Figure 1 shows a cross section and Fig. 2 a longitudinal section through a constructional embodiment of my invention. Fig. 3 is a section on line A-A on Fig. 2. Fig. 4 shows a cross section of a modified form of the apparatus and Figs. 5 and 6 show longitudinal andcross-section respectively of another modification.

B is the screen which is formed as a-cylinder and is completely submerged in the pulp .which is introduced at A. The inlet pipe A is made easily removable to make the several parts of the apparatus accessible. Inside the screening-cylinder is placed a second rotating cylinder D having two longitudinal suction channels S. and two longitudinal pressure channels T with openings on the'cylinder surface. The long annular space between the rotating'cylinder D and the screening cylinder B is d vided by means of longitudinal radial partitions I into separate chambers C, five such chambers being provided. At each end of the cylinder D the suction and pressure channels are connected with a centrifugal pump N which tends to maintain a constant suction 'and pressure respectively in the channels by means of the pump blades 0 and guide non-return valves or clappers' L.

vanes P. Asshown in Fig. thepressure channels '1 are closed at their ends and communicate through their sides with the space 1n the pump casing between the periphery of the latter and the outer ends of the blades .sothatthe pump actsto force the water and-stock in said channels toward the screen. 'jThe" suction channels are open at their ends rand communicate with the pump casing bet'ween the inner ends 'of the bladesand the'axis of rotation of the latter so thatj the pump tends to draw the .water from the'su ction channels; The stock sucked int'oj'the suction "channelsis partly let out at ;Q"'(Fig.' 3) andpartly' let into the pressure;"channels. 'The receptacle in- ClOSIIIg thefiscreening cylinder is provided with an easily 'removable cover R and at its bottom ihas'openings G' which may be opened'or shot by means of a lattice slide operated" from the lever M. At the cylinder ends removable covers W; are provided so as'to allow for cleaning the suction and pressure channels when the pump-wheels are disengaged from the rotating'drum D so the main-tank, said'pumps or .means keeping up a continuouscirculationof the mass between the chamber F and the main-tank. The outlet openings from the pumps J have. Instead of pumps ejectors Jxmay be used, (Fig. 4) part of the new .pulp beingused for ejecting purposes.

The operation of my apparatus is the following Thepulp to be screened is introduced at A in .a quantity large enough to wholly cover the screen cylinder. The cylinder D is rotated so as to create suction and pressure in the channels S and T by means of the pump N. the. wheels of which are rotated together with the cylinder D. Each time one of the suction channels S-is brought that they can be rotated independently of V under the screen surface the pulp stock is sucked through the screen and the suction-.

channels into the pump N, from where parts of the stock' is let out through the cooperate with the chamber C. above referred to and the pressure will cause the coarser fibers of the stock adhering to the screen plate to be expelled from the same. The'chambers C being one more in number than the suction and pressure channels, it is impossible for any of the chambers C to be exposed at the same time to suction and pressure. The part of the mass introduced at A and through the pumps J and which is not sucked through the screen plate sinks down to the bottom of the receptacle and is let out through the openings Gr to the chamber F. In the bottom of the main receptacle the shower pipe U will prevent the mass from packing. Through the openings G the stock together with waste and coarser particles flows into the chamber F, which is provided near its bottom with the grate H through whicha continual stream of water is flowing in an upward direction taking. with it the fine fibers of the stock and leaving the coarser particles and the waste on the grate. The finer fibers are returned by means of the pumps J to the main receptacle, where they are again exposed to the screening action.

When a sufiicient quantity of coarse pulp has accumulated on the grate H in the chamber F narrowing the area available for the flow of stock to a certain degree the velocity.

of flow will increase so that the coarser particles will also follow the current. To prevent this the openings G are closed at certain intervals by means of the lattice slide connected to the lever M and the waste islet out through the opening K. Owing to the non-return clappers L the fibrous mass from the main receptacle is prevented from flow ing into the chamber F during the emptying of same. The cleansing therefore can be effected without stopping the machine and as soon as the chamber F is emptied and the grate washed by means of the shower pipe V, the opening K is closed, andthe connection between the main receptacle and the chamber F is reestablished. The removable side wall R- serves to facilitate inspection and'repair of the interior parts of the screen.

Referring now to the modification shown on Figs. 5 and 6 the two suction channels S are here placed as shown near the outer surface of the rotating cylinder D, only one pressure channel T being provided in the middle of the cylinder having two openings one on each side of the cylinder D.

Only one pump is used at one end of the cylinder D to create suction in the two channels S and pressure in the pressure channel T. Guide vanes P arranged on the stationary end part of the apparatus to guide the mass into the channel T The screened pulp passes throughthe channel T into the end chamber N and out through the pipe Q. To keep pressure in the channel T a pressure tank X is connected to the pipe Q as shown on Fig. 6, this tank having an adjustable partition Y by means of which the pressure in the channel T, may be controlled. The screened pulp flows-over the partition Y and is let out at Z.

It is evident that the apparatus hereinbefore described can be modified in difierent ways within the scope of my inyention. Thus for instance the screening cylinder I might be made rotatable instead of the inner cylinder and the ribs I may be fixed on the inner cylinder instead of the-outer, etc. Also it is not necessary to form the two parts B and D as cylinders 'the same efi'ect may be attained by means of rotating disks or cones.

I claim: 1. ln pulsatingscreens iorpulp and the like a. stationary screeningcylinder, longitu-- dinal radial ribs inside said'cylinder dividing the cylinder into several sections, and a rotating member adapted to expose the several sections of the screen alternately to the action of pressure and suction channels.

2. In pulsating screen for pulp and the like a stationary screening cylinder, a rotating cylinder therein, being provided with suction and pressure channels having longitudinal openings on the surface of the cylinder, longitudinal radial ribs in the annular space between the inner rotating cylinder and the stationary screening cylinder, 'said longitudinal ribs dividing the said annular space into several sections which are evposed alternately to the action of the pressure and suction channels of the rotating cylinder.

3. lln pulsating screens for pulp and the like, a stationary screening cylinder, a rotating cylinder therein, provided with suction and pressure channels having longitudinal openings on the surface of the cylinder, and a pump in connection with the rotating cylinder for creating pressure and suction in the respective channels of the cylinder longitudinal radial ribs in the annular space between the inner rotating cylinder and the stationary screening cylinder, said longitudinal ribs dividing the screening cylinder into several sections, which are exposed alternately to the action of the pressure and suction channels of the rotating cylinder,'part of the pulp sucked into the suction channels being pressed by means of the pump-vanes into the pressure channels.

4. In pulsating screens for pulp and the like, a screening cylinder, a main receptacle inclosing said cylinder and adapted to be filled w1th pulp stock so as to completely cover the screening cylinder, an auxiliary chamber so connected with the said main receptacle that a continual circulation of the mass takes place from the said main rece'p-' tacle to the said chamber and back again to the main receptacle.

5. In pulsating screens for pulp and the like a pulsating mechanism, a-main receptacle inclosing the latter, anauxiliary chamber in connection with said receptacle, said main receptacle having openings leading to the said auxiliary chamber, a lattice slide for closing the said openings, a sloping grate in the bottom of the auxiliary chamber and below the said openings, means in the auxiliary chamber for effecting a circulation of the stockbetween the auxihary chamber and the main receptacle, said aumliary chamber havin anopening at the lower end of the said s oping grate for expelling waste and the coarser particles accumulated on the grate.

6, In pulsating screens for pul and the like, a main receptacle inclosing t e ulsating mechanism, an auxiliary cham r in connection with said receptacle, s'aid main receptacle having openings in its bottom leading to the said auxiliary chamber a sloping grate 1n the bottom of the latter and below the said openings, and means for 1 driving a slow current of water in an upward direction through the said grate, the said current taking with it the finer fibrous particles and leaving the waste and the coarser particles on the grate. a

7. In pulsating screens for pulp and the like, a main receptacle inclosing the ,ulsating mechanism, an auxiliary cham er in connection with said receptacle, said mainreceptacle having openings in its bottom leading to the said auxiliary chamber, a sloping grate'in the bottom of the latter and below the said openings, umps in the upperpart of the auxiliary c amber for efiectng a circulation of the stock from the chamber to the' main receptacle and nonreturn clappers for preventing the stock from returmng to the auxiliary chamber when said chamber isemptied.

8; In pulsating screens for pulp and the said grate partly to prevent the stock from packing in front of the said openings and partly for washing the grate.

9. In pulsating screens for pulp and the like, a stationary screening cylinder, a rotating cylinder therein, provided with suction and pressure channels having longitudinal openings on the surface of the cylinder, longitudinal radial ribs in the annular space between the inner rotating cylinder and the s stationary cylinder, a ressure chamber in connection with the said pressure channels receiving the separated pulp pressed through the pressure channels, an outlet pipe from said pressure chamber and means for adjusting the pressure in said pressure chamber.

10. In pulsating screens for pul and the like, a stationary screening cylin er, a rotating cylinder therein, provided with suc tion and pressure channels having longitudinal openings on the surface of the cylinder, longitudinal radial ribs in the annular space between the inner rotating cylinder and the stationary cylinder, a pressure chamber in connection with the said pressure channels for receiving the separated pulp pressed through the pressure channels, an outlet pipe from said pressure chamber, a pressure tank connected with said outlet pipe, an adjustable partition in the pressure tank for controlling the head of fluid in the latter and the pressure in the pressure chamher the separated stock flowing over the said partition in the'pressure tank.

In testimony that I claim the foregoing as my invention, Ihave signed my name in presence of two subscribing wltnesses.

NE'IF Errznu, M. E; GUTLOV Nnsrm. 

